<nav class="navbar navbar-default">
        <div class="container">
          <!-- Brand and toggle get grouped for better mobile display -->
          <div class="navbar-header">
            <button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#bs-example-navbar-collapse-1" aria-expanded="false">
              <span class="sr-only">Toggle navigation</span>
              <span class="icon-bar"></span>
              <span class="icon-bar"></span>
              <span class="icon-bar"></span>
            </button>
            <a class="navbar-brand" href="/">
                <img width="90px" src="/public/img/logo.png" alt="">
            </a>
          </div>
      
          <!-- Collect the nav links, forms, and other content for toggling -->
          <div class="collapse navbar-collapse" id="bs-example-navbar-collapse-1">
            <form class="navbar-form navbar-left">
              <div class="form-group">
                <input type="text" class="form-control" placeholder="Search">
              </div>
            </form>
            <ul class="nav navbar-nav navbar-right">
              {{ if user }}
              <li class="dropdown">
                <a href="#" class="dropdown-toggle" data-toggle="dropdown" role="button" aria-haspopup="true" aria-expanded="false"><img width="20" height="20" src="{{ user.avatar }}" alt=""> <span class="caret"></span></a>
                <ul class="dropdown-menu">
                    <li style="padding: 3px 20px;">
                    Hello {{ user.nickname }}
                    </li>
                    <li role="separator" class="divider"></li>
                    <li><a href="/settings/profile">个人设置</a></li>
                    <li><a href="/logout">退出</a></li>
                </ul>
              </li>
              <a href="/topic/new" class="btn btn-default navbar-btn">发起</a>
              {{ else }}
              <a href="/login" class="btn btn-primary navbar-btn">登录</a>
              <a href="/register" class="btn btn-success navbar-btn">注册</a>
              {{ /if }}
            </ul>
          </div><!-- /.navbar-collapse -->
        </div><!-- /.container-fluid -->
      </nav>